Conventional rolling mill laying heads employ three dimensional laying pipes which are formed by bending a straight length of pipe at high temperature around a forming fixture. The pipe is then allowed to cool, is cut, and has various locating blocks and bellmouths welded to it. It is then attached to a rotatable laying cone for operation.
In a modern high speed rod mill, laying heads must handle product at elevated tempertures in the range of 1600.degree. F. moving at speeds in excess of 10,000 f.p.m. Under such conditions, the laying pipes are subjected to severe wear, necessitating their frequent replacement. The form and accuracy of such laying pipes is critical. Pipes formed incorrectly, or which through age relieving or abuse become malformed, can cause serious problems in operation.
In the past, attempts have been made at prolonging the useful life of laying pipes by providing them with replaceable inserts. Such arrangements, as shown for example in U.S. Pat. No. 4,074,553, have not proven successful, due primarily to the difficulty of replacing worn inserts.